The present invention relates to a signal recording and reproduction system in which the time necessary for reproduction or playback of the desired playback section can be confirmed before the recording medium, which stores index data for the recorded contents, is played. The index data is called the TOC (Table of Contents) or the like. The recording medium may be an audio recording medium such as a compact disk or a digital audio recording medium (DAT), or a video recording medium such as a laser disk or video disk.
In the prior art, recording media of the digital recording type, including compact disks, have data known as subcode recorded together with the audio signal data. The subcode contains a time code indicating the total time length (in minutes and seconds or the number of frames covered) from the beginning of the recording medium. The subcode also contains the TOC or index data indicating the contents of the recorded data, including the total number of pieces of music recorded (or the number of music contents recorded), the time necessary for playing the whole program of music, and position data indicative of the start position of a given piece of music in the form of minutes and seconds and the number of frames as counted from the beginning of the particular recording medium. In the prior art, the function of indicating the remaining time is realized by the time code and TOC data contained in the subcode, and the function of indicating the time which is required for playing the whole program is realized by the TOC data.
FIGS. 8A and 8B show an example of the record contents of a recording medium and an example of the TOC data associated therewith. In these diagrams, numerals 1 to 6 designate the selection numbers or music numbers of the selections or pieces of music that are recorded. In this case, a total of six pieces of music are recorded. The start points T.sub.1 to T.sub.6 of the respective pieces of music 1 to 6 indicate the length of time from the origin 0 (00'00") of the recording medium. These time data are recorded as TOC data in the form of values as shown in FIG. 8B. The other TOC data recorded include the data N indicative of the total number of pieces of music to be played and the total play time T.
In a conventional system as shown in FIG. 9, the remaining time from the play position to the last point of the recording medium is indicated. That is, the information recorded in the recording medium 31 is reproduced by a reproduction means 32, which is operated by an operation means 33. The TOC data is stored in TOC data memory means 35 of a microcomputer 34, and the time code is detected by time code detection means 36. Also, the total play time T included in the TOC data stored in the TOC data memory means 35 is indicated by total play time indication means 37 (such as a liquid crystal indicator). Numeral 38 designates a remaining time calculation means, in which the constantly changing time t produced from time code detection means 36 is subtracted from the total play time T of the TOC data memory means 35 to thereby calculate the remaining time T.sub.X (=T-t). This remaining time T.sub.X is indicated by remaining time indication means 39. The relationship between the remaining time T.sub.X and the time t is shown in FIG. 10 in association with the recording medium shown in FIG. 8. The remaining time T.sub.X changes as the recording medium is driven, regardless of the start points T.sub.1 to T.sub.6 of the pieces of music 1 to 6 or midway thereof.
The remaining time is conveniently known in the conventional systems mentioned above. However, in the case where it is desired to know the play time for a desired reproduction section range covering intermediate pieces of music, for example, from the third piece of music to the end of the fifth piece of music, the procedure described below had to be followed. Firstly, the system is set in the reproduction mode. Then the remaining time indication T.sub.X1 at the end of the second music piece or the beginning of the third music piece is read, the remaining time indication T.sub.X2 at the end of the fifth music piece or the beginning of the sixth music piece is read, and the remaining time indication T.sub.X2 is subtracted from the remaining time indication T.sub.X1 (i.e., (T.sub.X1 -T.sub.X2) is calculated) to obtain the play time from the beginning of the third piece of music to the end of the fifth piece of music. These complicated and troublesome steps pose the problem that a user is required to make the calculation by himself.